1. Field of Invention
The present invention is directed to a downhole cutting tool and, in particular, a downhole radially expandable fluid jet cutting tool.
2. Description of Art
Various types of cleaning or cutting jet blasting arrangements have been proposed and used for jet blasting or eroding surfaces with abrasive fluids including, by way of example only, steam, water or any other fluid along with or without an abrasive substance in an attempt to accomplish whatever results may be desired.
Generally the fluids are conducted through a fluid passage in the arrangement and discharged through a restricted orifice in a jetting nozzle to increase the velocity of fluids and abrasive particles in an attempt to increase the cutting or cleaning effect desired. The jetting nozzle is available in a variety of designs and sizes and is normally produced from an extremely hard and/or tough material such as, by way of example only, carbide. It is generally accepted that the closer a jetting nozzle is to the surface to clean or cut the higher the efficiency of the operation.
One such prior jetting tool apparatus is disclosed in U.S. Pat. No. 5,765,756. The jetting tool apparatus of this patent includes multiple extendible telescoping jetting nozzles that are rotated into position by fluid flowing through the tool. In addition to rotation, the jetting nozzles extend telescopically so as to come in close contact with the cutting surface. After the cutting is completed, however, the nozzles remain extended. They are rotated downward into recesses to facilitate movement of the tool out of the wellbore. In those instances where the tool is to be moved to a new location for continued jetting, the telescopically extended jetting nozzles can not be reconfigured to a lesser extension because the telescoping members cannot be retracted to their original positions. As a result, the tool in U.S. Pat. No. 5,765,756 is limited in its use and requires removal of the tool from the well and resetting of the telescoping jetting nozzles before the tool can be used in a new, narrower, location. As is apparent, removal of the tool for resetting and subsequent repositioning in the well is time consuming and costly.